A general magnetic damping device for an exercising machine comprises two independent magnetic means and a magnetic plate disposed inside a load wheel. The magnetic means comprise arched plates, magnets, and tensile springs, wherein first ends of the tensile springs are connected to the arched plates and the second ends of the tensile springs are connected to the magnetic plate. By rotating and tightening the external adjusting knob, a steel rope is pulled to allow the arched plates and the magnets to approach the load wheel for increasing the magnetic damping force. By rotating and loosening the external adjusting knob, the arched plates and the magnets are pulled back by the tensile springs to depart from the load wheel for decreasing the magnetic damping force.
The conventional magnetic damping device has the magnetic plate and the tensile springs. However, the magnetic damping device has no structure for fine adjustment. As a result, it is very hard to provide the gaps between the magnets and the load wheel with accurate steady distances. Accordingly, the product has unstable quality and poor maintenance.